1. Field of the Invention
This invention relates to a method of brazing a pipe end portion of a metal pipe, which is generally used as a supply channel for automobiles or various machines, devices, or the like, to a counter member into which the pipe end portion is inserted to connect the metal pipe and the counter member.
2. Description of Related Art
To connect a pipe end portion, which is a vicinity of a pipe endmost portion of a pipe member, to an interior of a counterpart member securely, such a method has been generally taken that an outer peripheral surface of the pipe end portion and an inner peripheral surface of the counterpart member, in which a portion therebetween is defined as an abutment portion, are securely connected by brazing or soldering. Furthermore, a method as disclosed in Patent Document 1 has been widely known. In this method, the pipe end portion of the pipe member is inserted into the counterpart member and this inserted part of the pipe member is subjected to a swaging process from an exterior of the counterpart member to temporarily secure the pipe end portion and the counterpart member. The pipe member and the counterpart member are immersed in a melted metal to secure a connected part between the pipe member and the counterpart member as well as to form a metal coating on surfaces of the pipe member and the counterpart member.
As disclosed in Patent Document 2, a following method has also been widely known. That is, an expanded diameter portion in a ring shape is formed to an outer periphery of the pipe end portion of the pipe member to brought the expanded diameter portion into abutment with an inner peripheral surface of the counterpart member in an engaging manner by inserting the pipe end portion into a counterpart member so as to temporarily secure the pipe end portion of the pipe member and the counterpart member to each other. At the same time, a brazing filler metal is provided between an outer peripheral surface of the pipe member at the vicinity of the abutment portion and the inner peripheral surface of the counterpart member. The brazing filler metal is melted to braze the abutment portion between the expanded diameter portion of the pipe end portion and the inner peripheral surface of the counterpart member so that the outer peripheral surface of the pipe end portion and the inner peripheral surface of the counterpart member are securely connected.
Patent Document 1 is Japanese Patent Laid-Open No. 61-92773. Patent Document 2 is Japanese Patent Laid-Open No. 2-59171.
According to the invention disclosed in Patent Document 1, however, the pipe member and the counter member are immersed in the melted metal to cover the entire surface of both members with the metal. In this manner, the metal covers unnecessary parts, thereby causing waste. Furthermore, where the metal used for covering has a low corrosion resistance, the surface is required to be covered again with the metal with a high corrosion resistance. As a result, the production takes time and trouble while requiring a high production cost. Yet further, there is a case where the extra melted metal remains at the connected part between the pipe member and the counterpart member. In this case, there has been a fear that the remaining metal narrows a flow channel for liquid or gas that flows through the connected part between the pipe member and the counterpart member.
According to the invention disclosed in Patent Document 2, furthermore, since the brazing filler metal provided between the outer peripheral surface of the pipe member and the inner peripheral surface of the counterpart member is not positioned by securing or the like, there arises a case where the brazing filler metal is shifted to a position different from a desired position at the time of brazing operation. In this case, it has been difficult to perform the brazing operation to the desired position with accuracy.
This invention aims to solve the aforementioned problems and to provide a method of brazing the pipe member to the counterpart member, in which the pipe end portion of the pipe member and the counterpart member can be certainly secured by brazing at the desired position while this brazing operation is performed at a low cost without time and trouble.